SOCHI, Russia, Feb 17 (Reuters) - Americans Meryl Davis and Charlie White skated into the history books at the Sochi Winter Olympics on Monday when they won the ice dance gold, but thick fog in the mountains forced organisers to postpone two events and warn of more delays to come.

Belarus maintained their remarkable medal charge, picking up two more titles including gold for Darya Domracheva, who is now the only woman to have won three biathlon titles at the same Games after her 12.5km mass start victory.

In the biggest contest of the day at the Feb. 7-23 Olympics, another record fell.

Davis and White became the first Americans to win the Olympic ice dance title with a spellbinding performance to the music of Rimsky-Korsakov's "Scheherazade".

While their dazzling display thrilled the crowd packed into the Iceberg Skating Palace, spectators in the mountains were disappointed by the postponement of the men's biathlon 15km mass start and men's snowboard cross competitions until Tuesday.

"We're so excited we're kind of in shock a little. I'm not sure what we're feeling," a beaming Davis told reporters after improving on their silver medal finish from four years ago.

White added: "To come away with a gold medal is amazing ... And 17 years of hard work was justified."

Weather delays may extend further into the final week of the Games, officials have warned, with the women's giant slalom possibly turning into a two-day affair.

Safety was organisers' main concern after a series of injuries at the Rosa Khutor Extreme Park, as fog and drizzle replaced a week of uninterrupted sunshine in the Caucasus peaks high above Sochi.

The worst accident involved Russian ski cross athlete Maria Komissarova, who was flown to a specialist clinic in Germany on Sunday for a second operation after having had lengthy surgery to attach a metal plate in her spine.

LATE GOLD RUSH

After a series of weather-related delays, Domracheva won the first title of the day at around 7:30 p.m.

The 27-year-old said support from Russians in the crowd meant it was almost like skiing at home.

"I am thankful to the people who support me. Without their support it'd be harder," she told a news conference. "I was hearing 'Dasha, Dasha' from the tribune.

"Russian family, Belarussian family. All these nations, Russians, Belarussians, we are like brothers and sisters. For me, I feel this country is really native for me," she added.

Hours later, compatriot Anton Kushnir won the men's freestyle skiing aerials competition to take Belarus to seventh in the medals table with five golds - one more than Canada.

Russia moved up to second in the rankings, with gold in the two-man bobsleigh.

Alexander Zubkov secured the Olympic title he came out of retirement to win, as Russia's flagbearer at the Games' opening ceremony proved uncatchable on home ice.

Germany leads the world with six days of competition to go, securing an eighth Olympic title with the last event of the day - the men's team ski jumping.

The Games lost one of its top athletes when Norway's Aksel Lund Svindal decided to leave without competing in his final two races after failing to win a medal. Expectations had been high after he showed great form this season.

"NEW" PUTIN ON SHOW

Komissarova's injury and weather disruptions have been the biggest blights so far on Russia's first Winter Olympics, where thrilling action and futuristic venues have dispelled some of the doubts that marred the buildup to the Games.

President Vladimir Putin has joined the crowds at the Olympic Park in Sochi and up in the mountains, engaged in cosy chats with teams and Olympic officials and even turned up at Komissarova's bedside to offer support.

This is the "new" Putin on show. Pictures of him in action - riding horses bare-chested or shooting a tiger with a tranquiliser dart - have at least for now been carefully put to one side.

The Russia that Putin wants to portray at the Games is a caring country that has come a long way since the austere days of the Soviet Union. The leader he wants to portray is a man with whom the West can do business.

In one of only a few isolated incidents of dissent so far in Sochi, a transgender former member of Italy's parliament was detained by Russian police for the second time in 24 hours on Monday for trying to stage a gay rights protest at the Olympics.

Vladimir Luxuria said she was led away by two men in plain clothes on Sunday when she held up a sign saying "Gay is OK" in Russian in the Olympic Park and was held for about three hours.

She was allowed into the park again on Monday but barred from watching an ice hockey match because she was wearing a rainbow headdress - the colours of the lesbian, gay, bisexual and transgender movement - and had a gay pride flag.

Luxuria was protesting against Russian legislation banning homosexual propaganda among minors, which caused international outcry leading up to the Olympics. Critics say it discriminates against gays and has fuelled violence against homosexuals.

International Olympic Committee spokesman Mark Adams told reporters: "We hope that the Games will not be used as a platform for demonstrations."

Separately, a Russian man was detained in Sochi for demonstrating against the jailing of an environmentalist angered by the effects of huge Olympic construction projects.

A regional court last week rejected Yevgeny Vitishko's appeal against a three-year prison sentence on charges of damaging the regional governor's property, which he denies.

Vitishko's supporters say he is being punished for publicising environmental problems caused by the Olympics, and say the case was politically motivated.

He has begun a hunger strike in protest at his treatment, said his organisation Environmental Watch on the North Caucasus.

Putin has dismissed criticism of environmental damage, his stance on gay rights and the high costs of the Games, which some estimates put at $51 billion. That would make Sochi the most expensive Olympics ever, although the figure is disputed. (Reporting by Reuters Olympic team in Sochi and Rosa Khutor; Editing by Peter Rutherford)